Photonic transceiving device package structure
The apparatus includes a case having a base member, two partial side members, and a lid member to provide a spatial volume with an opening at a back end of the base member. Additionally, the apparatus includes a PCB installed inside the spatial volume over the base member with a pluggable connector at the back end. The apparatus includes one or more optical transmitting devices in transmit-optical-sub-assembly package, each being mounted upside-down on the PCB and including a built-in TEC module in contact with the lid member and a laser output port aiming toward the back end. Furthermore, the apparatus includes a silicon photonics chip including a fiber-to-silicon attachment module, mounted on the PCB and coupled to a modulation driver module and a trans-impedance-amplifier module. Moreover, the apparatus includes an optical input port and output port being back connected to the fiber-to-silicon attachment module.
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This application is continuation of and claims priority to U.S. patent application Ser. No. 14/789,290, filed on Jul. 1, 2015, now issued as U.S. Pat. No. 9,496,959 on Nov. 15, 2016, commonly assigned and incorporated by reference herein for all purposes.BACKGROUND OF THE INVENTION
The present disclosure is related to a photonic transceiver package structure, more particularly, to a silicon photonic transceiver package structure that conforms to the Quad Small Form-factor Pluggable (QSFP) specification adapted for multiple Thermoelectric Cooler-Transmitter Optical Sub-Assembly (TEC-TOSA) laser devices disposed upside down to heat sink away from a printed circuit board (PCB) with reversed orientation of laser output port relative to optical input/output port of the transceiver module.
As science and technology are progressing rapidly, processing speed and capacity of the computer increase correspondingly. The communication transmission or reception using the traditional cable is limited to bandwidth and transmission speed of the traditional cable, but the mass information transmission required in modern life causes the traditional communication transmission overload. To address such requirements, the optical fiber transmission system replaces the traditional communication transmission system gradually. The optical fiber transmission system does not have bandwidth limitation, and also has advantages of high speed transmission, long transmission distance, its material is impervious to electromagnetic waves. Therefore, the electronics industry performs research toward optical fiber transmission which will become the mainstream in the future. Said optical communication is a technology in that light waves function as signal carriers and transmitted between two nodes via the optical fiber. Field of optical communication can be divided into optical communication side and electric communication side according to transmission medium. By the optical transceiver, the received optical signal can be converted to an electrical signal capable of being processed by an IC, or the processed electrical signal can be converted to the optical signal to be transmitted via optical fiber. Therefore, objective of communication can be achieved.
Wavelength-division multiplexing (WDM) is a multitask technology of processing multiple optical carrier signals transmitted by the optical fiber, and this technology is applied on the different wavelength signal or transmission of laser optical source. This technology is implemented in both directions on the optical fiber to double total transmission capacity. Besides, the term “wavelength-division multiplexing” is mostly applied in optical carrier, and frequency-division multiplexing is applied in radio carrier. Moreover, both of wavelength and frequency are in reciprocal relationship, so their concept can be applied to each other.
Wavelength-division multiplexing is implemented by dividing the work wavelength of optical fiber into multiple channels to enable mass data transmission in one optical fiber. A whole wavelength-division multiplexing (WDM) system can be divided into a wavelength division multiplexer at transmitting end and a wavelength division demultiplexer at receiving end. At present, there are commercial wavelength division multiplexer/demultiplexer which can divide 80 or more channels in the optical fiber communication system, so that the data transmission speed can exceed grade of Tb/s effectively.
In both transmitting and receiving ends of the optical fiber communication system, the transmitting module adapted for WDM technology, the connector usually has single light transmitter structure. However, such light transmitter structure can emit optical signals with different frequencies, but cannot be repaired for individual frequency. Therefore, whole light transmitter must be replaced if being damaged, and it causes larger consumption in cost.BRIEF SUMMARY OF THE INVENTION
The present disclosure is related to a photonic transceiver package structure, more particularly, to a silicon photonic transceiver package that conforms to the Quad Small Form-factor Pluggable (QSFP) specification adapted with multiple thermoelectric-cooled transmitter optical sub-assembly (TEC-TOSA) laser devices disposed upside down to place heat sinks away from a printed circuit board (PCB) and laid reversely in laser output port orientation relative to optical input/output port of the transceiver. In certain embodiments, the invention is applied for high bandwidth optical communication, though other applications are possible.
In modern electrical interconnect systems, high-speed serial links have replaced parallel data buses, and serial link speed is rapidly increasing due to the evolution of CMOS technology. Internet bandwidth doubles almost every two years following Moore's Law. But Moore's Law is coming to an end in the next decade. Standard CMOS silicon transistors will stop scaling around 5 nm. And the internet bandwidth increasing due to process scaling will plateau. But Internet and mobile applications continuously demand a huge amount of bandwidth for transferring photo, video, music, and other multimedia files. This disclosure describes techniques and methods to improve the communication bandwidth beyond Moore's law.
Serial link performance is limited by the channel electrical bandwidth and the electronic components. In order to resolve the inter-symbol interference (ISI) problems caused by bandwidth limitations, we need to bring all electrical components as close as possible to reduce the distance or channel length among them. Stacking chips into so-called 3-D ICs promises a one-time boost in their capabilities, but it's very expensive. Another way to achieve this goal in this disclosure is to use multiple chip module technology.
In an example, an alternative method to increase the bandwidth is to move the optical devices close to electrical device. Silicon photonics is an important technology for moving optics closer to silicon. In this patent application, we will disclose a high speed electrical optics multiple chip module device to achieve terabits per second speed, as well as variations thereof.
In a specific embodiment, the present invention provides an apparatus for packaging a photonic transceiver. The apparatus includes a case, comprising a base member, two partial side members being connected by a joint piece and coupled to the base member, a lid member including a cover coupled to the two partial side members and the base member to provide a spatial volume with an opening at a back end of the base member. The apparatus further includes a PCB installed inside the spatial volume over the base member. The PCB includes a board body extended from a front edge to a back edge. The back edge is near the opening at a back end of the base member. The board body includes an array of metallic pin stripes at the back edge to form a pluggable electrical interface connector. Additionally, the apparatus includes one or more optical transmitting devices. Each of the one or more optical transmitting devices is mounted upside-down on the PCB near the front edge and includes a TEC module being in thermal contact with the lid member and a laser output port aiming toward the back edge. Furthermore, the apparatus includes a silicon photonics chip mounted on the PCB. The silicon photonics chip includes a fiber-to-silicon attachment module to couple with a first fiber from each of the laser output port. Moreover, the apparatus includes an optical input port and an optical output port disposed together on a front end of the base member near the joint piece for the two partial side members. Each optical input port and optical output port is back connected via a second fiber to the fiber-to-silicon attachment module.
Therefore, the present disclosure has at least following advantages. First, the package structure for the photonic transceiver of the present disclosure can be detached independently, so that assembly engineer can replace single photonic transceiver in failure. Secondly, the PCB board and cylindrical element of a transmitting device of the present disclosure can be detached and detected individually, so that the cylindrical element provided with the coupling lens can be recycled for reuse when the transmitting module is damaged. Thirdly, the reversed output orientation of the transmitting device relative to the transceiver output port provides easy access for the laser output fiber to couple with a silicon photonics chip on the PCB. Fourthly, the upside-down disposition of the transmitting laser device on PCB with its TEC base attached to the lid member away from the PCB, enhancing heat dissipation efficiency for the transmitting laser device.
The present invention achieves these benefits and others in the context of known memory technology. However, a further understanding of the nature and advantages of the present invention may be realized by reference to the latter portions of the specification and attached drawings.
The following diagrams are merely examples, which should not unduly limit the scope of the claims herein. One of ordinary skill in the art would recognize many other variations, modifications, and alternatives. It is also understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this process and scope of the appended claims.
The present disclosure is related to a photonic transceiver package structure, more particularly, to a silicon photonic transceiver package structure in QSFP specification adapted with multiple TEC-TOSA laser devices disposed upside down to keep heat sinks away from PCB and laid reversely in orientation of laser output port relative to optical input/output port of the transceiver. In certain embodiments, the invention is applied for high bandwidth optical communication, though other applications are possible.
The following description is presented to enable one of ordinary skill in the art to make and use the invention and to incorporate it in the context of particular applications. Various modifications, as well as a variety of uses in different applications will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to a wide range of embodiments. Thus, the present invention is not intended to be limited to the embodiments presented, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without necessarily being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.
The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All the features disclosed in this specification, (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
Furthermore, any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. Section 112, Paragraph 6. In particular, the use of “step of” or “act of” in the Claims herein is not intended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.
Please note, if used, the labels left, right, front, back, top, bottom, forward, reverse, clockwise and counter clockwise have been used for convenience purposes only and are not intended to imply any particular fixed direction. Instead, they are used to reflect relative locations and/or directions between various portions of an object.
As shown in
In an embodiment, the photonic transceiver 200 includes one or more transmitting devices 210 installed on the PCB 220 near the front edge 225. In a specific embodiment, each of the transmitting devices 210 is a TEC-TOSA (thermoelectric cooled transmit optical sub-assembly) laser device. Each TEC-TOSA laser device 210 is configured (via a transmitting module inside) to produce one laser light at a specific wavelength outputted through a laser output port 215 with a single-mode fiber 212 and is coupled into a fiber-to-silicon photonics attachment module 231 pre-fabricated on the silicon photonics chip 230 which is mounted on the middle region of PCB 220. The fiber-to-silicon photonics attachment module 231 includes multiple V-grooves for coupling the optical fibers with silicon waveguides (not visible in
In a specific embodiment, there can be at least two TEC-TOSA laser devices 210 in each QSFP package 100, which needs two MZ modulators correspondingly for the two channels of wavelengths of laser light. As mentioned in
On the other hand, the photonic transceiver device 200 is configured to receive optical signal via optical input port 218 which is passed through a single fiber 211 to the silicon photonics chip 230 first via the fiber-to-silicon attachment module 231. Then a demultiplexer (not visible in
In a specific embodiment, the silicon photonics chip 230 is coupled to a PAM4 driver module 234 for driving two MZ modulators (single stage or multi-stage) for providing optical signal modulation. The PAM4 driver module 234 includes a PAM encoder and a FEC encoder with CDR Rx I2C interface coupled to ASIC chip 201 for converting data to optical signal in 4×10 G to 4×25 G rate. The PAM4 driver module 234 is based on 28 nm CMOS technology. Additionally, the silicon photonics chip 230 is also coupled to a TIA module 235 for processing electrical signals and converting them to digital signals. The electrical signals are converted by one or more PDs from demultiplexed light signals out of an incoming optical signal received from the optical input port 218. The TIA module 235, also based on 28 nm CMOS technology, includes PAM ADC/DSP CDR and PAM decoder with CDR Tx interface coupled to ASIC chip 202 for converting optical signal to digital signal in 4×10 G to 4×25 G rate for converting optical signal to digital signal in 4×10 G to 4×25 G rate and provide electrical interface communication with Ethernet network via the pluggable multiple metallic pin stripes 222.
In a specific embodiment, the TEC-TOSA laser device 210 is laid in a reversed configuration with laser output port 215 pointing toward the back edge 226 of the PCB 220, just opposite to that of the conventional transceiver device whose laser output port is pointed to the optical fiber output port 219 (with a LC connector) near the front end 105 of the photonic transceiver package 100 (see
In another specific embodiment, shown in
In yet another specific embodiment, the photonic transceiver 200 in this embodiment applies technology of wavelength-division multiplexing (WDM), two or more TEC-TOSA laser devices 210 to use a Distributed Feedback (DFB) or Fabry-Perot (FP) laser diode to generate laser light of different wavelengths at any channels of dense-wavelength-division-multiplexing spectrum band. Two channels can further be combined into one single-mode optical fiber via wavelength-division multiplexer for middle distance and long distance transmission. Next, the received optical signal is performed a light-split process by the demultiplexer and the split optical signals are introduced to different channels. In this embodiment, except WDM technology, the photonic transceiver package 100 also can be applied to related optical communication technologies, such as binary phase shift keying modulation (BPSK), quadrature phase shift keying modulation (QPSK), conventional/coarse wavelength division multiplexing (CWDM), dense wavelength division multiplexing (DWDM), and optical add/drop multiplexer (OADM), reconfigurable optical add/drop multiplexer (ROADM).
The coupling lens assembly 351 comprises a square metal outer part 3511 fixed on a flat surface of the TEC module 340 in front of the annular hole 324, holding a lens body 3512. The lens body 3512 comprises an aspherical lens with curved surfaces on both sides having radius of curvature changes according to distance from the optical axis for achieving improved laser light coupling efficiency. During manufacturing process, filler material is sealed into a space over the transmitting module 312 between the cover 313 (see
The cylindrical element 315 of the laser device 310 is mounted on the assembling part 322 correspondingly connecting to the laser output port 215 (with the optical fiber 212 as shown in
Further shown in
Further in a specific embodiment, the isolator 3152 is disposed in a mechanical body 31521 (
While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims.
1. An apparatus for packaging a photonic transceiver comprising:
- a case, comprising a base member, two partial side members being connected by a joint piece and coupled to the base member, a lid member including a cover coupled to the two partial side members and the base member to provide a spatial volume with an opening at a back end of the base member;
- a PCB, installed inside the spatial volume over the base member, including a board body extended from a front edge to a back edge, the back edge being near the opening at an back end of the base member, the board body comprising an array of metallic pin stripes at the back edge to form a pluggable electrical interface connector;
- one or more optical transmitting devices, each being mounted upside-down on the PCB near the front edge and including a TEC module being in thermal contact with the lid member and a laser output port aiming toward the back edge;
- a silicon photonics chip, mounted on the PCB, including a fiber-to-silicon attachment module to couple with a first fiber from each of the laser output port;
- an optical input port and an optical output port disposed together on a front end of the base member near the joint piece for the two partial side members and respectively back connected via a pair of second fibers to the fiber-to-silicon attachment module; and
- a pull handle having two arms coupled to respective front ends of the two partial side members.
2. The apparatus of claim 1 wherein each of the optical input port and the optical output port comprises a LC connector accessible from the front end by an optical fiber in a mate LC connector.
3. The apparatus of claim 1 wherein the optical input port and the optical output port are configured to fit a multi-fiber push-on (MPO) connector accessible from the front end by two optical fibers.
4. The apparatus of claim 1 wherein the optical transmitting device comprises a transmitting module, a TEC module, and a coupling lens assembly, the transmitting module being mounted on the TEC module via a first submount and the coupling lens assembly being directly mounted on the TEC module next to the transmitting module, all being enclosed in a space by a TEC base member and a cover member.
5. The apparatus of claim 4 wherein the TEC base member comprises a plane part having a hollow region formed from a top surface to a bottom surface for disposing a second submount on which the TEC module is mounted, the second submount being leveled with the bottom surface of the plane part and the first submount on the TEC module being above the top surface of the plane part.
6. The apparatus of claim 5 wherein the optical transmitting device comprises a circuit board having a flat end with electrical pins for coupling with connection spots on the PCB and a U-shaped end with electrical connection spots for mounting on the top surface of the plane part of the TEC base member.
7. The apparatus of claim 6 wherein the transmitting module comprises a thermistor, a MPD (monitor photodiode) chip, and a LD (laser diode) chip, all being mounted on the first submount attached on the TEC module and being respectively wire bonded to the electrical connection spots in the U-shaped end of the circuit board on the top surface of the plane part.
8. The apparatus of claim 7 wherein the TEC base member further comprises an assembly part substantially vertically connected to both the top surface and the bottom surface of the plane part, the assembly part having an annular hole disposed to align with the coupling lens assembly mounted on the TEC module at a predetermined distance from the LD chip.
9. The apparatus of claim 4 wherein the optical transmitting device comprises a filler material sealed the space by infusion and welding.
10. The apparatus of claim 8 wherein the optical transmitting device comprises a Z-space member having one end fixed to the assembly part at side opposite to the plane part with an alignment to the annular hole and another end coupled with a cylindrical receptor element, the Z-space member being configured to calibrate X-Y positions relative to the annular hole before being fixed.
11. The apparatus of claim 10 wherein the optical transmitting device further comprises an isolator fixed inside a sleeve body between the Z-space member and the cylindrical receptor element subjecting to a Z-axis calibration to determine an optimal distance of the isolator from the coupling lens assembly and an optical fiber connection mechanism coupled a fiber through the cylindrical receptor member and a ferrule.
12. The apparatus of claim 1 wherein the silicon photonics chip comprises one or more silicon-based MZ (Mach Zehnder) modulators, a plurality of photo diode detectors, a wavelength-division multiplexer, and a wavelength-division demultiplexer, the one or more silicon-based MZ modulators modulating light of different wavelengths received via the fiber-to-silicon attachment module from respective laser output ports of the multiple optical transmitting devices, the wavelength-division multiplexer being coupled to the multiple silicon-based linear MZ modulators to combine the light of different wavelengths after modulation before outputting via the fiber-to-silicon attachment module to the optical output port, and the wavelength-division demultiplexer being coupled to the fiber-to-silicon attachment module to demultiplex an optical signal from the optical input port to a light with multiple wavelengths respectively detected by the plurality of photo diode detectors.
13. The apparatus of claim 1 further comprising a pair of ASIC chips mounted on the PCB near the back edge respectively coupled with a modulation driver module and a TIA module, both being wire bonded to the silicon photonics chip.
14. The apparatus of claim 13 wherein the modulation driver module is based on CMOS technology including a PAM encoder and a FEC encoder with 2 channels CDR Rx I2C interface to drive the one or more silicon-based MZ modulators for modulating light from the one or more optical transmitting devices.
15. The apparatus of claim 13 wherein the TIA module is based on CMOS technology including PAM ADC/DSP CDR and PAM decoder with 2 channels CDR Tx interface to provide electrical interface communication with Ethernet network via the pluggable electrical interface connector.
16. The apparatus of claim 1 wherein the one or more optical transmitting devices include two laser devices in a TEC-based transmit optical sub-assembly package.
17. The apparatus of claim 1 further comprising a QSFP specification pluggable to network system allowing data rates of 4×10 Gbit/s, 4×28 Gbit/s or higher.
18. The apparatus of claim 7 wherein the LD chip comprises a FP photo diode with DFB package capable of producing a laser light with wavelength in one of DWDM spectrum channels.
19. The apparatus of claim 1 wherein the one or more optical transmitting devices are reversely laid on the PCB such that the laser output ports are aiming backward from the optical input port and the optical output port.
20. The apparatus of claim 1 wherein the fiber-to-silicon attachment module comprises multiple V-grooves fabricated on the silicon photonics chip for coupling optical fibers to silicon waveguides.
21. The apparatus of claim 1 wherein the silicon photonics chip is configured to receive one or more light signals externally from the one or more optical transmitting devices via the fiber-to-silicon attachment module coupled with the first fiber from each laser output port.
22. The apparatus of claim 7 wherein the TEC module being contacted with the lid member comprises a direct pathway for dissipating heat via the second submount to any external heat sink attached to the lid member.
23. The apparatus of claim 1 wherein the cover of the lid member comprises two side edges partially overlapping with the two partial side members and having two first clip structures for coupling with two partial side members and two second clip structures for coupling with the base member.
Filed: Oct 10, 2016
Date of Patent: Jun 6, 2017
Patent Publication Number: 20170031117
Assignee: INPHI CORPORATION (Santa Clara, CA)
Inventors: Radhakrishnan L. Nagarajan (Santa Clara, CA), Peng-Chih Li (Santa Clara, CA), Masaki Kato (Palo Alto, CA)
Primary Examiner: Tesfaldet Bocure
Application Number: 15/289,894
International Classification: G02B 6/12 (20060101); H04B 10/00 (20130101); G02B 6/42 (20060101); H04B 10/40 (20130101); H04J 14/02 (20060101); H04B 10/516 (20130101); G02B 6/30 (20060101); G02F 1/225 (20060101); G02F 1/21 (20060101);